J
jack of all trades 博而不精的`人，萬事通
join in 參加，參與
jump to a conclusion 貿然斷定;過早下結論
just as well 無所謂，也好
justify in doing sth 有理由做某事
K
keep an eye on 照看，注意，觀察
know/learn the ropes 瞭解、掌握做事情的技能!
keep body and soul together 生存下去
keep in touch with 與通訊，保持聯絡
keep ones head 保持鎮靜
keep sb. informed 及時通知某人
keep sth. in good order 使處於良好狀態，使井井有條
keen on 喜好
kill time 消磨時光
keeping up with the Joneses 老和別人攀比
